Wireless transmission system



C. S. FRANKLIN.

WIRELESS TRANSMISSION SYSTEM.

APPLICATION FILED JAN-3,1920.

Patented Nov. 23, 1920..

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CHARLES SAMUEL FRANKLIN, OI LONDON, ENGLAND, ASSIGNOR, BY MESNE' ASSIGN- MENTS, TO RADIO CORPORATION OF AMERICA, OF NEW YORK, N. Y A CORPORA- TION OF DELAWARE.

WIRELESS TRANSMISSION SYSTEM.

Specification of Letters Patent.

Patented Nov. 23, 1920.

Application filed January 3, 1920. Serial No. 349,251.

7 '0 all whom it may concern Be it known that 1, CHARLES SAMUEL FRANKLIN, a subject of the King of Great Britain, residing at Marconi House, Strand,

London, England, have invented new and useful Improvements in Wireless Transmission Systems, of which the following is a specification.

' This invention relates to improvements in multi-aerial wireless transmission systems.

It is known that if oscillations of a predetermined phase are maintained in a number of transmitting aerials spaced 'apart at distances which are a considerable proportion of the wave length, very useful eifects, particularly directional, can be obtained from the system. For instance, if oscillations of the same intensity and phase are maintained in two aerials spaced apart a half wave length, the system radiates powerfully in the direction at right angles to the line between the two aerials and not at all in the direction of this line; if, however, the oscillations maintained in the two aerials spaced apart as above are of equal intensity and opposite in phase, then the radiation is most powerful in the direction of the line joining the aerials and zero in the direction at right angles. Again, if oscillations of equal intensity and having a phase difference of 90 are maintained in two aerials spaced apart a quarter wave length, the radiation is a maximum in one direction of the line joining the two aerials and zero in the opposite direction. By combining a number of spaced aerials, which may be either of the directional or non-directional type, and controlling the oscillations in them a variety of useful effects can be obtained.

A system of spaced aerials may be supplied from a central oscillation generator, such as a single or multi-phase alternator, an are or a thermionic oscillation valve, the oscillations being conveyed to the aerials by circuits com rised of parallel wires properly arranged. uch a system however is liable to be inefiicient owing to the losses in the conveying circuits.

According to this invention I provide each of the aerials of a system with an oscillation generator of the threeelement thermionic type, power being preferably supplied to each generator from some common source, and I control the fre uency of each generator from a central in ependent generator, the oscillations of which are led to the grid circuits of all the generators coupled to the aerials so as to control the frequency and phase therein.

The invention is illustrated in the accompanying drawing as applied to two aerials A A at any desired fraction of a wave length apart.

The oscillations in the two aerials are generated by valves V V, respectively, the power being supplied by a dynamo D and conveyed to each valve by wires P P This is however a matter of convenience as, if desired, each valve may have its own independent source of power.

CV is a control valve of relatively smaller power and situated at some convenient place, preferably equidistant from the two aerials. This control valve is arranged to generate oscillations of the desired frequency.

A coil M in the anode circuit of the control valve is coupled to coils N N connected through tuning condensers F F to lines L L which convey the oscillations from the control valve to transformers T T the secondaries of which are connected to the grids of the valves V V and control the frequency and phase of the oscillations generated by them.

The frequency is determined by the valve CV and the phases by the tuning of the circuits comprising the primaries of the transformers T T the lines L L the condensers F F and the coils N N respectively. The phases may also be controlled by the tuning of the aerials A A It is necessary to arrange the twin leads of L and L so that the waves radiated by A and A affect them equally and produce no reaction efiect on the valves V V or CV.

What I claim is 1. In a wireless telegraph transmitting system, the combination of a number of independent aerials, a separate valve for each aerial, acentral generator and tuned circuits coupling the central generator to the and tuned circuits coupling the control generator to the local generators.

3. In a Wireless telegraph transmitting system, the combination of a number of independent spaced aerials, a separate generator of oscillations for each aerial located in proximity thereto, a control generator and tuned circuits connecting the control generator to each of the separate generators adapted to control the oscillations generated 10 by each of the separate generators.

In testimony that I claim the foregoing as my invention I have signed my name this tenth clay of December, 1919.

CHARLES SAMUEL FRANKLIN. 

